Deciphering Limitations to Meet Highly Stable Bio‐Hybrid Light‐Emitting Diodes

Color down‐converting filters with fluorescent proteins (FPs) embedded in a polymer matrix have led to new bio‐hybrid light‐emitting diodes (Bio‐HLEDs), featuring stabilities of 100 h and 300 h at high driving currents. Here, the photoinduced deactivation mechanism takes place, consisting of a slow and reversible partial dehydration followed by a quick and irreversible deactivation of the highly emissive ionic form. This is supported by steady‐state/time‐resolved emission, circular dichroism, and electrochemical impedance spectroscopic techniques. Overall, the limitations of Bio‐HLEDs concerning matrix, buffers, device design, and FP stability are highlighted as key aspects to achieve efficient and stable devices. The first steps toward the optimization of bio‐hybrid light‐emitting diodes are presented. Using a remote architecture, the thermal quenching of fluorescent proteins (FPs) upon excitation is circumvented. This increases the device stability from a few minutes to hundreds of hours. The FP deactivation is rationalized using spectroscopic assays to obtain valuable insight about the FP structural modifications under device operating conditions.